Retrievable Filter Screen Assembly

ABSTRACT

A retrievable filter screen assembly is provided, comprising a nonmagnetic carrier sub suspended from a first pulling tool connected to a wireline; a nonmagnetic filter screen disposed within the carrier sub, and having a first end supported by a bell housing operatively positioned within the carrier sub, and wherein the first end of the filter screen can be disconnected from the bell housing via shear pins; wherein the filter screen further includes a second end adapted to receive a second pulling tool positionable within the carrier sub, and wherein the pulling tool is connectable to an MWD source.

CROSS-REFERENCE TO RELATED APPLICATIONS

This nonprovisional application claims the benefit of priority to provisional application U.S. Ser. No. 61/691,525, filed on Aug. 21, 2012.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON COMPACT DISC

Not applicable.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to devices and methods used in oil and gas drilling operations to filter drill pipe scale, dried cements and other debris from drilling fluids, and more particularly to such devices which are retrievable/retrieving and connectable to commonly used measurement while drilling (MWD) and similar downhole devices.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements.

FIG. 1 shows a cross-sectional view of a preferred embodiment of the invention, depicting a filter screen mounted within a sub present within a well bore.

FIG. 2 shows an exploded view of the various components of the embodiment of FIG. 1.

FIG. 3 shows a detail view of the filter screen used in connection with the invention.

DETAILED DESCRIPTION OF THE INVENTION

Before the subject invention is further described, it is to be understood that the invention is not limited to the particular embodiments of the invention described below, as variations of the particular embodiments may be made and still fall within the scope of the appended claims. It is also to be understood that the terminology employed is for the purpose of describing particular embodiments, and is not intended to be limiting. Instead, the scope of the present invention will be established by the appended claims.

In this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs.

Turning now to the figures, FIG. 1 and FIG. 2 generally show a cylindrical carrier sub 4 suspended by a wireline 9 within a well casing 8. A filter screen 2 is operatively positioned within the carrier sub 4 and supported by a bell housing 1. The bell housing 1 further includes an O-ring 3 circumferentially located around the exterior surface of the bell housing 1 to establish a seal between the bell housing 1 and the carrier sub 4.

In an operating configuration, a pulling tool 7 (such as a GS series pulling tool) is connected to the bell housing 1 and to the wireline 9. A plurality of shear pins 5 are present between the filter screen 2 and the bell housing 1 to permit disconnection of the filter screen 2 under suitable circumstances. Another pulling tool 6 (such as JD series pulling tool) is connected below the filter screen 2, and is connectable to any number of downhole devices, including measurement while drilling (MWD) devices 10.

FIG. 3 provides a more detailed view of the filter screen 2, depicting the plurality of slots 11 for filtration of the drilling fluids. The slots 11 are formed and sized to account for the total flow area around and through the filter screen 2, which permits maximum flow rates with minimal erosion effects, and a low chance of total blockage by debris.

Based on the foregoing design features, it will be appreciated that the filter screen 2 can be retrieved and reseated as desired, and that the present invention further includes the ability to retrieve an MWD source 10. Thus, the present invention provides the advantage of protecting debris from obstructing the MWD source 10, and also enables the operator to retrieve the filter sub 4 and MWD source 10 in one trip in the event of a stuck condition.

The carrier sub 4 and filter screen 2 are preferably manufactured in any size suitable for the downhole conditions, and can be fabricated using steel or other nonmagnetic material, giving the operator the ability to place the invention in multiple locations in the bottom hole assembly (BHA) or above.

All references cited in this specification are herein incorporated by reference as though each reference was specifically and individually indicated to be incorporated by reference. The citation of any reference is for its disclosure prior to the filing date and should not be construed as an admission that the present invention is not entitled to antedate such reference by virtue of prior invention.

It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention set forth in the appended claims. The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims. 

The invention claimed is:
 1. A retrievable filter screen assembly, comprising: (a) a nonmagnetic carrier sub suspended from a first pulling tool connected to a wireline; (b) a nonmagnetic filter screen disposed within the carrier sub, and having a first end supported by a bell housing operatively positioned within the carrier sub, and wherein the first end of the filter screen can be disconnected from the bell housing via shear pins; wherein the filter screen further includes a second end adapted to receive a second pulling tool positionable within the carrier sub, and wherein the pulling tool is connectable to an MWD source. 